Add. $9 + 6.4 =$
Answer: There are many ways to solve this problem. Let's see two ways we can solve it. Place value table Let's line up the numbers by their decimal places. Ones $.$ Tenths ${9}$ $.$ ${0}$ $6$ $.$ ${4}$ Because $9$ is a whole number, we can add a decimal point and a $0$ behind to make the columns align. Now, let's add each place value column. Tens Ones $.$ Tenths ${9}$ $.$ ${0}$ $+$ ${6}$ $.$ ${4}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $1$ $5$ $.$ $4$ Decomposing the numbers We can group the whole numbers together and the decimals together. $\begin{aligned} &(9 + 6) + {0.4}\\\\ &=15 + {0.4}\\\\ &=15.4 \end{aligned}$ $9 + 6.4 =15.4$